Speed boat



March 1 1927. 1,618,995

J. PLUM SPEED BOAT Filed Feb. 11. 1925 2 Sheets-Sheet 1 FlGl. E: U D

1767 axnn es Plum March 1,1927.

J. PLUM SPEED BOAT Filed Feb. 11. 1925 2. Sheets-Sheet 2 13 3a 50 3a 29 3: 2? H67.

37 T; as 35 34- 2 2 5 53 4'4 Johannes Plum FIGFIZ 32W Patented Mar. 1, 1927.

UNITED STATES JOHANNES PLUM, OF WASHINGTON, DISTRICT OF COLUMBIA.

SPEED BOAT.

Application filed. February 11, 1925. Serial No. 8,549.

This invention relates to improvements in boats of the speed boat and hydroplane type and has for its object to construct such boats so that they can be driven at high speeds with very small consumption of power. Such a boat is able to carry heavy loads without having its speed influenced to any great extent. An object of this invention is to provide a boat with a longitudinally concave bottom or planing surface so that the boat will be adapted to plane on the surface of the water. It is a further object of this invention to apply an aquaplane to the boat which is rotatable but which is also mounted to move vertically and is provided with shock absorbing means for the vertical movement. A still further object is to provide the propelling means of the boat where its operation will not disturb the medium upon which the boat is travelling. In other words the medium upon which the device is travelling such as air or water should be undisturbed and therefore the propeller is placed and provided upon the device so that its rotation will not disturb the supporting medium. Further objects of the invention are included in the shock-absorbing device of the aquaplane and the character of the propeller shaft.

Further objects will be apparent from'the following specification taken in connection with the accompanying drawings in which like reference characters refer to corresponding parts throughout and in which:

Figure l is a plan view of a boat and an aquaplane,

Fig. 2 is a cross section of an ordinary boat'hull shown speedingthrough the water,

Fig. 3 is a cross sectionof a boat hull ac cording to the present invention shown speeding through the water.

Fig. 4 is a side elevation view of the novel speed boat shown speeding through the water,

Fig. 5 is a plan View of the boat shown in Fig. 4,

Fig. 6 is a cross-sectional view of the hull taken on line 66 of Fig. 5,

Fig. 7 is a cross-sectional view of the shock absorbing means of the hydroplane,

Fig. 8 is a side view of a hydroplane,

Fig. 9 is a cross section .of the pontoon taken on line 9-9 of Fig. 8,

Fig. 10 is a fragmentary side View of an ordinary boat shown speeding on the water,

Fig. 11 is a cross-sectional view of the novel propeller shaft,

. Fig. 12 is a side View thereof, and I Fig. 13 is a cross-sectional view of a modified form of propeller shaft.

It is a well known fact that a speed boat has its speed influenced to a noticeable extent by the addition of a person or in other words the added weight of 150 lbs. This influence is especially noticeable in boats of small dimensions, as shown and indicated by the numeral 1 in Fig. 1, such as for instance a 28 H. P. boat making a speed of 19 knots per hour which is reduced to 12 knots by the addition of two passengers or the added Weight of 300 lbs. If, however,

this 300 lbs. be placed upon an aquaplane 2 the'speed of the boat is almost 19 knots with, of course, the same consumption of fuel. This 'must indicate that the pull on the rope 3 is extremely small and. if the rope be adjusted so that the aquaplane be made to travel on the stern wave created by the boat, the force on the rope can be practically reduced to zero. By further increasing the weight on the aquaplane 2 it is noticed that the aquaplane was able to plane entirely on the surface of the Water with as heavy a load as 100 lbs. per square foot of its bearing surface; while an increase of weight of only '5 to 6 lbs. per square foot on the speed boats bearing sur-- face makes the stern travel as if buried in the w ater, thus impeding the speed 'considerably. The result thus obtained by the aquaplane indicates that the carrying power of the water surface is far greater than imagined.

The main difference between the construction of the aquaplane and the speed boat, is, that the first is moved by a tow-line, while the speed boat is moved by a propeller. By examining the operation of the propeller it has been found that the propulsion 1s caused by the propellers blades, each'of which throws a certain volume of water backward, at the rate of 2000 times to the minute, which means, that every minute for a three blade propeller 6000 such volumes are moved from the place in front of the propeller, to the rear of the boat; and all the water which the propeller utilizes in this wa is taken from immediately beneath or directly behind the bearing surface of the boat. It therefore appears that the speed boats immense amount of power is utilized in such a way that it digs a cavity beneath the boat thus removing a great amount of water which otherwise the boat could utilize as a planing surface. It is thus apparent that the speed boat travels with its stern down in the hollow of the water, while its carrying plane is constantly on the edge of that waterfall that is rushing down into the hole formed by the operation of the propeller. Fig. 2 shows the boat hull 4 riding in the hollow portion 5 the dotted line 6 indicating the water level and solid line 7 indicating the water level of the hollow portion. 'It will be seen from the drawing that the hull is supported on the edges 8 of the bottom of the hull and the center of the hollow forms a vacuum space 9 since the propeller is liable to take away more water than is able to flow in and, therefore, the pressure of the atmosphere will do its utmost to press the stern of the boat down into this hollow portion.

lVhen considering the carrying power of the water surface it must be remembered that a surface boat while planing is not carried by the weight of the volume of water which the hull displaces, but is solely supported by the resistance which the water particles offer in being moved so suddenly. The power of this resistance can be easily understood when one bears in mind that the water molecule cannot be compressed, or at least only to a negligible extent, and therefore a water molecule acted upon by the bottom of the boat is, before it can give way, compelled to thrust aside its surrounding molecules and those in turn are compelled to. do likewise to their neighboring molecules. Therefore, before the boat is able to set one molecule of water in motion, it must have power or weight enough to set countless molecules in motion and when such power is required to overcome the resistance of only one of all those molecules which are directly touched by the boat, it is easily understood, why-the carrying power of the water surface is so immense for a speeding plane. Thus by removing volumes of water from under the boat, the most important factor for the surfaces sustaining power is annulled, as the affected water molecules then have a chance to escape, instead of being compelled to set up a resis' tance.

A speed boat constructed to utilize the sustaining force of the water is i llustrated in Figs. 4 and 5 inwhich the propeller is so far removed from that part of the surface, which is supporting the boat while planing, that there will always remain a supporting volume of water between the cavity caused by the operation of the propeller and that part of the water surface which supports the boat. Furthermore the boat 10 is provided with a longitudinally concave bottom portion or surface 11 in a portion of its hull, in order to enable the entire planing surface to act upon the water molecules even after they have been depressed by the forepart of the plane. Fig. 3 shows a cross section of the hull and also shows how the surface of the water 12 is substantially straight and does not form a hollow as indicated in Fig. 2. The boat 10 is provided with a bridging portion 13 and at the end of said bridge a hydroplane 14 is mounted which is freely rotatable as indicated in the dotted line position 15 in Fig. 5. This hydroplane is r0- tatably mounted in order to accommodate itself in rounded curves so that the edges of the plane shall not catch the water and cause the boat to upset.

The boat is further provided with a propeller 16 driven and mounted on shaft 17 which is in turn rotated by the engine 18. As indicated in Figs. 4 and 5 the propeller shaft projects through the bottom of the boat, for example, at the end of the concave bottom portion at 19 and then extends a con siderable distance rearwardly to the propeller. The object of this long shaft is. to remove the propeller a considerable distance from the planing surface 11 so that said surface shall pass over undisturbed water since the propeller in its rapid operation forms a hollow immediately in front of it. The hydroplane is adapted to bear approximately on the stern wave created by the planing surface of the boat. For clearly illustrating these features attention is directed to Fig. 4 in which the water section indicates at 20 the planing surface, 21 the hollow formed by the rotation of the propeller and 22 the stern wave which supports the plane 14, it of course being understood that this figure represents the boat travelling at high speed. When the boat is travelling very slowly or is motionless, it of course sinks into the water thus acting as a displacement boat and not as a surface boat when in motion at high speed. Fig. 6 illustrates the approximate depth at which the boat sinks into the water when it acts as a dis lacement boat, the line 23 indicating the sur ace of the water and the dotted line 24 indicating the surface of the water when the boat acts as a surface boat.

As stated in the foregoing, the entire hydroplane 14 is movable vertically in order to adjust its planing surface relative to the surface of the water upon which it is planing and also to act as a shock absorber when travelling on rough water, as for instance, when the stern is suddenly forced upwardly or downwardly. The plane is secured to a rod 25 which isprovided with a piston 26 operating in cylinder 27. At the upper part of this cylinder an air chamber 28 is formed which is supplied with compressed airby means of pipe 29 from storage tank 30. Air

can be suitably supplied to said tank by a suitable hand pump 31 and by means of valve 32 air can be admitted into chamber 28 in any desired amounts and thus obtain the correct adjustment of the position of the piston and therefore the hydroplane. By any suitable valve, not shown, secured to the cylinder 27 air can be exhausted from chamber 2b if desired. The lower part of the cylinder is provided with a chamber 33 which has a pipe 34 secured thereto which leads to a hand pump 35. A tank 86 is in communication with pump 35 andlhis system is adapted to be filled with glycerine. In order to secure a cushion effect an air trap 37 is arranged in conmiunication with pipe 34 and thus the hydroplane and its pis ton will adapt itself to downward movements of the stern of the boat. The hand pump 35 is for the purpose of regulating the pressure of the glycerine in chamber 33.

Fig. 8 shows the invention applied to a hydroplane in which the aeroplane 38 is pro vided with a pontoon 39 or a pair of them which shows the lon itudinal concave bot tom or planing surfade 40. It will be noted that the water follows the bottom surface 01:

the pontoon and thus supports it along its entire length while in the case of a flat bottom 41 shown in Fig. 10 the Water surface will only contact at a small port-ion 42 thereof when the boat or pontoon is travelling at high speed. Fig. 9 shows a cross section of the pontoon and illustrates how the fiat bottom of the float rides on the surface of the water. plane will easily and quickly lift itself from the water since there is a tendency to force the pontoon upon the surface of the water thus reducing the resistance of the water.

Figs. 11 and 12 illustrate a portion of the.

propeller shaft and it will be seen that the shaft is provided with teeth or edges 43 which are adapted to cut their Way through the water during rapid rotation, when the boat is travellingat a high rate of speed. It is a known fact thatwhen a barv or rod is forced through water at high speed a tremendous resistance is set up to prevent its passage therethrough but if it is provided with teeth or cutting edges this resistance can be greatly reduced due to the drilling effect of the revolvin shaft. Therefore, instead of the propel er shaft 17 being round and smooth, teeth or edges are provided thereon and Fig. 13 illustrates a modified form of shaft in which the edges 44 are somewhat less pointed, the arrow indicating the direction of the rotation in both modifications.

Fig. 8 also shows the propeller 45 arranged at the rear of the hydroplane and it is so situated for the same reason that the pro- It will thus be seen that the hydroconcave bottom portion; a bridging porlion; and a hydroplane secured at the rear of the bridging portion.

A speed boat having a longitudinally concave bottom portion; a bridging portion; and a hydroplane secured at the rear of the bridging portion, said hydroplane being mounted to rotate freely.

4. A speed boat having a longitudinally concave bottom portion; a bridging portion; and a hydroplanesecured at the rear of the bridging portion, said hydroplane being mounted to rotate freely, and being adjustable vertically.

5. A hydroplane adjusting meansfor a speed boat; comprising a piston secured to the hydroplane; a cylinder for said piston; and means for adjusting the position of the piston in the cylinder.

6. A hydroplane adjusting means for a speed boat; comprising a piston secured to the hydroplane; a cylinder for said piston; an air tank in pipe communication with the top of said cylinder; and means for ad usting the position of the iston in the cyl nder.

'7. A hydroplane a justing means for a speed boat; comprising a' piston secured to thehydroplane having an upper and a lower surface; a cylinder for said piston; an air tank in pipe communication with the upper part of said piston; a pump for regulating the air in the tank; a shock-absorbing system for the lower surface of said piston;

and means for adjusting the position of the piston in the cylinder.

8. A surface boat having'a planing surface in its bottom portion; and a hydroplane secured at the rear of the boat, said hydroplane being mounted to rotate freely in a horizontal plane.

9. A surface boat having a planing surface in its bottom portion; a bridging portion; and a hydroplane secured at the rear of the bridging portion, said hydroplane being mounted to rotate freely in a horizontal plane.

10. A surface boat having a planing surface in its bottom portion; and a hydroplane secured at the rear of the boat, said hydroplane being mounted to rotate freely'ln a horizontal plane and being ad uStable vertically.

11. A surface boat having a planing surface in its bottom portion; a bridging portion; and a hydroplane secured at the rear of the bridging portion, said hydroplane be 5 ing mounted to rotate freely in a horizontal plane and being adj llStiLble vertically.

12. A speed boat having a planing surface in its bottom portion; and a verticallyniovable hydroplane mounted at the rear of the boat the plane of the hydroplane being 10 at all times approximately horizontal.

13. A speed boat comprising a freelyrotatable hydroplane secured in the rear end of the boat, said hydroplane being rotatable in an approximate horizontal plane.

In testimony whereof I aflix my signature.

JOHANNES PLUM. 

